Color imaging devices contain two or more cartridges. Each transfers a different color of toner to a media sheet as required to produce a full color copy of a toner image. A common imaging device includes four separate color cartridges of toner—cyan, yellow, magenta, and black. Image formation includes moving toner from a reservoir to an imaging unit where toned images, black or color, are formed on photoconductive (PC) drums prior to transfer to a media sheet or to an intermediate transfer member (ITM) for subsequent transfer to a media sheet.
When transferring to an ITM, such as an endless belt, electrically biased backup rolls align with and create a nip with the PC drums that the ITM moves through in an endless loop. Polyurethane foam or other soft material forms the backup rolls so that the nip is relatively pliable. A controller directs application of differing voltages from a power supply to the drums and backup rolls that causes electrostatic transfer of the toned image from the drums to the ITM. This, however, requires the imaging device to have a complex power supply and necessitates power cabling from the power supply to the rolls, both of which add cost to the imaging device. A need exists to overcome the foregoing and other problems.